Daypack - Alternatives to Lowepro ComouDay Photo 250?

Thanks for the comments. I have a belt holster which I use when I know I am going to be taking photos and there isn´t a security risk. I take your point about thief´s access to a side access flap, when I´m in a crowd I wear my current backpack on my chest.

What I was hoping to find was a day bag I can take out every day and keep my DSLR in it, in case of an unexpected photo opportunity. I´m not necessarily looking for instant access to the camera, but don´t want to have to put the bag down to get my camera out - as in town it is often impractical to do so. It seems a bit of a waste of an investment on a DSLR if it stays at home most of the time & I can only carry a small point and shoot.